Exploring the watery remains of France's sunken Roman port of Olbia

Stretching over four sandy kilometres Almanarre beach in southern France is a mecca for sun lovers and kite surfers. But its greatest treasure — a 2,000-year-old underwater archaeological site — lies just a few feet offshore. Welcome to the port of the ancient Roman city of Olbia, which fell victim to a slow rise in Mediterranean waters, but is still open for visits from explorers equipped with a snorkel mask and pair of flippers. A collection of rectangular limestone blocks, some perfectly aligned, others scattered about on the seafloor, make up the watery remains of the dock of the city of Olbia, a fortified trading post founded by the Greeks in the 4th Century BC on the outskirts of the modern-day Riviera town of Hyeres. After the capture of nearby Marseille by Julius Caesar in 49 BC the region gradually came under the control of the Roman empire, which endowed Olbia with a port in the 1st Century AD. The 100-metre (yard) dock was only used for 80 years, according to marine archae